Electric motors or generators have generally a core stator consisting of magnetic thin iron laminations, usually between 0.35 and 0.5 mm thickness, which form the annular assembly. The stator core is usually secured to an external casing, the latter firmly fixed to the machine foundation. The stator core may consist of lamination packets separated by radial ventilation ducts. Other designs can require axial ducts for the same purpose of cooling. On the surface of the stator core, slots are equally spaced, generally having a rectangular shape. The stator winding is laid down in these slots. Typically one or two bars or coils are present in every slot. The rotor is generally coaxial with the stator and is magnetically coupled to the stator. The rotor comprises a rotor body and a rotor winding, the latter generally fixed within rotor slots. The stator winding is generally connected to a 3-phase electric grid, whereas the rotor winding is usually fed by an external source to produce the magnetic field necessary for electromagnetic induction. The rotor speed can be either synchronous or asynchronous with respect to the armature magnetic field. Electrical power is generated from the armature winding. The bars or coils comprise a kernel, which is generally constituted by a plurality of copper strands, each insulated from the others, and an outer layer of insulation which can be specifically designed for high voltages. The stator winding is generally firmly fixed into the corresponding slots by wedges and other means, like lateral, radial wedges, filler strips and resin, to reduce the winding vibrations thus preventing insulation damages and slot discharges. There are several different stator bars technologies, depending mainly on the generator power output. It is differentiated between direct and indirect cooling designs by gas and/or by a cooling medium. The commonly today used cooling medium is de-ionized water. The connection between the stator bars has mainly two tasks, to lead the current and to lead the cooling medium. It is recommended to separate the electrical and hydraulic circuits to increase the bar to bar connection reliability, thus the whole generator reliability. To this end hollow conductors and water boxes from stainless steel have been introduced in which the two current and hydraulic circuits are split. However, today many generator bars still are equipped with hollow conductors from copper and can be replaced with stainless steel solutions only if complete stator rewind will be offered. Moreover, many machines suffer from cooling medium leaks especially if the brazing of some stator bars elements is not done properly or if the special prevent design is not put in place to mitigate design weaknesses. Therefore a solution is required to split both circuits and thus assure the certain water box reliability and tightness. Cooling medium leakage can occur which will lead to reduced cooling capabilities of the stator bars or the cooling medium will start the corrosion of the Cu-hollow conductors, finally leading to a reduced generator lifetime.